# Copyright (c) 2019 Presto Labs Pte. Ltd.
# Author: xguo

import json
import logging
from typing import List, Union

from tornado import gen

import coin.flow.topic_map as topic_map
from coin.base.param_util import to_list
from coin.exchange.base.ws.subscriber import WebsocketJsonSubscriberBase
from coin.exchange.bitstamp_v2.ws.private_subscriber import (
    parse_channel_name,
    get_channel_name,
    EventType,
    ChannelType,
)


class BitstampSubscriber(WebsocketJsonSubscriberBase):
  def __init__(self,
               queue,
               group_id: str,
               worker_id: str,
               symbol: Union[List[str], str],
               close_callback=None,
               logger=None):
    super().__init__(close_callback, logger or logging.getLogger(__name__))
    self._symbol = to_list(symbol)

    self._register_url('wss://ws.bitstamp.net')
    self._publisher = None
    self._init_publisher(queue, group_id, worker_id)

  def _init_publisher(self, queue, group_id: str, worker_id: str):
    topic_depth = topic_map.search_topic_id('bitstamp_ws_depth_%s%s' % (group_id, worker_id))[0]
    topic_trade = topic_map.search_topic_id('bitstamp_ws_trade_%s%s' % (group_id, worker_id))[0]

    self._publisher = {
        ChannelType.ORDER_BOOK: queue.get_writer(topic_id=topic_depth[1]),
        ChannelType.TRADE: queue.get_writer(topic_id=topic_trade[1])
    }

    self._enable_topic_event_publisher(queue,
                                       'bitstamp_ws_topic_event', [topic_depth[0], topic_trade[0]])
    self._add_teardown_callback(self._teardown_publisher)

  @gen.coroutine
  def on_open(self):
    yield self._send_subscribe_request()

  @gen.coroutine
  def _send_subscribe_request(self):
    for symbol in self._symbol:
      self._logger.debug('Subscribing %s' % symbol)
      subscribe_depth_str = json.dumps({
          "event": EventType.SUBSCRIBE.value,
          "data": {
              "channel": get_channel_name(ChannelType.ORDER_BOOK, symbol),
          }
      })
      yield gen.sleep(0.5)  # Sleep 0.5 second before next request
      yield self._ws.write_message(subscribe_depth_str)

      subscribe_trade_str = json.dumps({
          "event": EventType.SUBSCRIBE.value,
          "data": {
              "channel": get_channel_name(ChannelType.TRADE, symbol),
          }
      })
      yield gen.sleep(0.5)  # Sleep 0.5 second before next request
      yield self._ws.write_message(subscribe_trade_str)

    self._publish_topic_event('START')
    self._logger.info('Subscribe done')

  def _teardown_publisher(self):
    if self._publisher:
      for _, publisher in self._publisher.items():
        publisher.close()
      self._publisher = None

  def on_message(self, timestamp: int, message: dict):
    if self.stopped:
      return

    event = EventType(message['event'])
    if event == EventType.SUBSCRIPTION_SUCCEEDED:
      self._publish_topic_event(message)
    elif event in (EventType.DATA, EventType.TRADE):
      channel_type = parse_channel_name(message['channel'])['channel_type']
      if channel_type in (ChannelType.ORDER_BOOK, ChannelType.TRADE):
        try:
          self._publisher[channel_type].write(timestamp, message)
        except (KeyError, ValueError):
          self._logger.error('Unknown channel: %s' % message)
    else:
      self._logger.error('Unexpected message received! %s', message)
